Generally, an image processing apparatus, such as a multifunctional peripheral (MFP) including a printer, scanner, facsimile machine, and copier or functions thereof, includes a communicating medium (such as a NIC (Network Interface Card) or modem (Modulator-Demodulator)) that communicates with an external apparatus (such as a computer or other image processing apparatuses) through a communication medium such as a network or telephone lines. Some of such image processing apparatuses include a function (hereinafter, a sleep function) for shifting to a power-saving state (generally, referred to as a sleep mode) with lower power consumption than a normal operation state if no operation is performed for an operation input unit included in the image processing apparatus and no data are received from the external apparatus through the communicating medium for a certain time period or more. In the power-saving state, for example, energization (power supply) is discontinued for a fixing device including a heater and devices such as a control circuit, while the communicating medium is often maintained in an energized state. This is because in the power-saving state, energization of devices in a non-energized state is resumed in response to a request from the external apparatus to allow the devices to automatically return to the normal operation state. For example, in an image forming apparatus shown in Japanese Laid-Open Patent Publication No. H8(1996)-101606, when an energized communicating medium receives a print request in a power-saving state, the entire apparatus is energized to form an image in accordance with the received print request.
The requests from the external apparatuses include various requests such as a print request that requests to form an image on a recording paper sheet, an image scan request that requests to read an image formed on a document, and a request for performing a process of accessing a storage unit such as a hard disk included in the image processing apparatus to manipulate a data file (hereinafter, a data filing process). The data filling process may be processes of writing or updating data, reading data, erasing data, and changing data file names, for example.
On the other hand, in an image forming apparatus shown in Japanese Laid-Open Patent Publication No. 2005-186425, when an energized controller receives an access request for a hard disk from an external apparatus through a network in a power-saving state, energization of the hard disk is started to perform the requested process.
In an MFP shown in Japanese Laid-Open Patent Publication No. 2003-63101, when a print request is received through an external interface in a power-saving state where a sub-CPU and the external interface are supplied with electric power from a sub-power source, the sub-CPU supplies electric power to a main CPU controlling the entire apparatus to perform printing.
However, when an apparatus is in a power-saving state and some sort of process is requested by an external apparatus through a communicating medium, if energization is always started for many non-energized devices due to the request to perform the requested process, it is problematic that sufficient power-saving cannot be achieved.
Particularly, in the case of an MFP including many devices corresponding to a variety of functions and shared by many users, many types of requests are received from external apparatuses through a communicating medium and the requests may have different degrees of importance or urgency. Therefore, it is important for achieving further power-saving to energize the required minimum devices at an appropriate timing depending on contents of a request received during the power-saving state.